Thursday, August 24, 2017

A national regulatory policy that cuts the nicotine content of cigarettes may decrease the addiction potential of cigarettes—and those effects would extend to populations highly vulnerable to tobacco addiction, according to a study published Wednesday in JAMA Psychiatry.

In late July, the Food and Drug Administration proposed reducing nicotine levels in tobacco products to decrease the chances of people becoming addicted and help currently addicted smokers to quit.

“Evidence in relatively healthy and socially stable smokers indicates that reducing the nicotine content of cigarettes reduces their addictiveness,” lead author Stephen T. Higgins, Ph.D., a professor and vice chair of psychiatry at the University of Vermont in Burlington, said in a press release. “Whether that same effect would be seen in populations highly vulnerable to tobacco addiction was unknown.”

The study consisted of a double-blind, within-participant assessment of acute response to “research cigarettes” with nicotine content ranging from levels below a hypothesized addiction threshold to those representative of commercial cigarettes (0.4 mg/g, 2.3 mg/g, 5.2 mg/g, and 15.8 mg/g of tobacco) at three academic sites. A total of 169 daily smokers (120 women, 49 men) from three vulnerable populations—people with affective disorders (n=56), people with opioid dependence (n=60), and socioeconomically disadvantaged women (n=53)—completed 14 experimental sessions lasting two to four hours each.

After smoking their usual-brand cigarette in the first session, participants smoked one research cigarette of varying doses of nicotine under double-blind conditions for sessions 2 to 5. Participants were required to use a plastic cigarette holder when smoking research cigarettes, to measure smoking topography—the number of puffs, length, and speed of each puff. A Cigarette Purchase Task was completed after each smoking session to measure the effects of cost on the participant’s rate of smoking. Additional questionnaires assessed nicotine withdrawal, smoking urges, and nicotine dependence.

For sessions 6 to 11, participants were asked to select the cigarette they preferred of two options (six different dose combinations were offered over this phase of trial). A computer program recorded which of the two cigarettes participants preferred for each session and whether or not they wanted to continue to smoke that selection after two puffs or abstain. The final phase of the trial (sessions 12-14) followed the same protocol, but measured only the highest and lowest doses of nicotine.

While participants tended to prefer the higher nicotine dose cigarettes, the researchers found that the low-nicotine dose cigarettes could serve as economic substitutes for higher-dose commercial-level nicotine cigarettes when the cost of the latter was greater.

“Reductions in reinforcing effects were achieved in the present study without causing untoward withdrawal, craving, or compensatory smoking,” Higgins and colleagues noted.

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